The invention relates to a cerium oxide dispersion, to a process for producing it and to its use.
Cerium oxide dispersions are used in the semiconductor industry to polish SiO2 (CMP). Cerium oxide dispersions are known from EP 1 596 940. These cerium oxide dispersions have particles with a mean aggregate diameter d50 of less than 200 nm.
The known cerium oxide dispersion disadvantageously includes at least one dispersant.
In addition, the known cerium oxide dispersion includes further additives which are used for STI CMP and are intended to shift the selectivity during the polishing of SiO2 and Si3N4 in favour of the SiO2.
The known cerium oxide dispersion also has the drawback that it has SiO2 removal rates of <600 nm/min and is additionally unstable, since the cerium oxide forms a sediment (cf. DE 101 62 174 A1, U.S. Pat. No. 6,312,486).
The object therefore exists of producing a cerium oxide dispersion which does not have these drawbacks.